The invention relates to a testing system for chemical substances or substance mixtures and to a method of testing chemical substances or substance mixtures for their activity, especially for testing potential plant protection compositions, such as insecticides, fungicides, herbicides and the like.
WO 86/04919 discloses a method for the in vitro culturing of plant cells which comprises applying freely movable buoyant bodies to the surface of the liquid nutrient medium and culturing the plant constituents on the surface of those buoyant bodies. Also disclosed is a culturing vessel having additional devices for the supply and removal of liquids or gases, for the circulation thereof in the vessel and for the regulation of physical and chemical variables.
EP-A-0 323 205 describes a device for the application of herbicides by means of a rod-shaped arrangement on which spray nozzles are mounted.
The testing of chemical substances or substance mixtures (for the sake of simplicity reference is made always to one substance hereinafter) for their activity, especially the testing of potential plant protection compositions (pesticides), such as insecticides, a fungicides, herbicides, nematicides, acaricides and the like, is nowadays generally carried out by bringing plants or parts of plants, for example sections of leaves, into contact with the substance to be tested. Where the aim of the test is merely to discover whether or not the substance as such is able to cause damage to the leaf section (for example in the case of a herbicide) there is no need for the leaf section to be infested with a pest, a fungus or the like; otherwise the leaf section needs also to be infested with the appropriate pest, fungus or the like (for example when the substance is a fungicide or insecticide). After some time the leaf section is examined for the activity of the substance applied.
As a rule, the substance to be tested is applied to the leaf section manually using a pipette or in the case of entire plants is generally sprayed on. Since the number of substances which it is desirable to test for activity is very large and is steadily and rapidly increasing, the manual application of the individual substances using a pipette, although possible in principle, has only a limited degree of suitability because it is very complicated and time-consuming, so that the steadily increasing number of substances which it is desirable to test for activity cannot be managed in this way in practice and requires the constant employment of qualified personnel. Moreover, it is also difficult to wet the test specimen (e.g. leaf sections, comminuted parts of plants, seeds or entire plants) evenly with the substance to be tested, so that it is hard to obtain reliable information about the activity of a substance. If a number of test specimens, arranged one next to the other, are sprayed with different substances there is also a risk that a neighbouring test specimen will become contaminated, so that thereafter the action of the substance tested on the neighbouring test specimen may affect or even completely falsify the result.
An aim of the invention is therefore to provide a method of testing pesticides and a testing system for carrying out that method which does not have the disadvantages mentioned above and which therefore allows, especially, a high throughput of substances to be tested and specimens to be tested, while at the same time allowing reliable identification and categorisation of the test specimens and of the substances tested, in which, furthermore, contamination of neighbouring test specimens is ruled out and which is automated to the highest possible degree, so that it is particularly efficient, that is to say, for example, it is also able to operate overnight and without supervision.
That problem is solved by the method according to the invention and by its testing system. According to the invention there is therefore proposed a method of testing pesticides for their activity, wherein the pesticide to be tested is applied to a test specimen, especially to plants or parts of plants, such as sections of leaves and the like, and, after a predetermined period of time has elapsed, the test specimen is examined for the activity of the pesticide, in which method first of all a type of test specimen is selected from a stock of test specimens, and the pesticides to be tested are selected from a stock of pesticides to be tested; the selected type of test specimen and the selected pesticides are then identified (BC1, BC2) by means of a machine-readable code and those codes are supplied to a memory unit (12), the test specimens being placed in readiness in a carrier plate (30) by deposition of each test specimen or a section (BR) of test specimen in a well (300) that is provided in the carrier plate (30) and is at least partly filled with a nutrient solution (301) or a gel and the carrier plate being thus charged; and then either a spraying device (150, 151, 158) is positioned immediately above the well(s) (300) of the carrier plate (30) and sprays the test specimen deposited therein with the pesticide, or the spraying device (150, 151, 158) is inserted into the well(s) (300) of the carrier plate (30) and sprays the test specimen deposited therein with the selected pesticide and is then removed from the well (300) again.
Preferably the pesticides are herbicides, fungicides or insecticides.
Preference is given to a method wherein first of all a type of test specimen is selected from a stock of test specimens, and the substances to be tested or the substance mixtures to be tested are selected from a stock of substances or substance mixtures to be tested; the selected type of test specimen and the selected substances or the selected substance mixtures are then identified (BC1, BC2) by means of a machine-readable code and those codes are supplied to a memory unit (12), the test specimens being placed in readiness in a carrier plate (30) by deposition of each test specimen or a section (BR) of test specimen in a well (300) that is provided in the carrier plate (30) and is at least partly filled with a nutrient solution (301) or a gel and the carrier plate being thus charged; and then a spraying device (150, 151, 158) is inserted into the well(s) (300) of the carrier plate (30) and sprays the test specimen deposited therein with the selected substance or the selected substance mixture and is then removed from the well (300) again.
Preference is given also to a method wherein first of all a type of test specimen, e.g. a specific plant variety, is selected from a stock of test specimens, and the substances to be tested or the substance mixtures to be tested are selected from a stock of substances or substance mixtures to be tested; the selected type of test specimen and the selected substances or the selected substance mixtures are then identified (BC1, BC2) by means of a machine-readable code and those codes are supplied to a memory unit (12), the test specimens being placed in readiness in a carrier plate (30) by deposition of each test specimen or a section (BR) of test specimen in a well (300) that is provided in the carrier plate (30) and is at least partly filled with a nutrient solution (301) or a gel and the carrier plate being thus charged; and then a spraying device (150, 151, 158) is positioned immediately above the well(s) (300) of the carrier plate (30) and sprays the test specimen deposited therein with the selected substance or the selected substance mixture.
In an especially preferred embodiment of the method according to the invention the test specimen is first conveyed to a stamping device (2) which automatically stamps out a section, for example a leaf roundel (BR), from the test specimen, retains the stamped-out section after it has been stamped out and then deposits it in a well (300) in the carrier plate (30) that is at least partly filled with nutrient solution (301) or a gel.
More especially preferred is an embodiment wherein a plurality of substance concentrates or substance mixture concentrates, each is of which has been deposited in wells in a plate, are placed in readiness in a second inlet storage means (8), and a mixing device (13) is provided for the preparation of the substance to be applied to the test specimen, or of the substance mixture to be applied to the test specimen, from the concentrate present in the well in question and an auxiliary mixture (11), and the substance so prepared or the substance mixture so prepared is then conveyed to the spraying device (150, 151, 158).
The test specimen is especially an entire plant.
The testing system according to the invention for carrying out the method comprises a first inlet storage means (5) in which a large number of carrier plates (30) charged with test specimens is stored temporarily before spraying.
Preference is given to a testing system wherein the spraying device comprises a nozzle body (150) having a sealing ring (152) which is so arranged that, on insertion of the nozzle(s) (151) of the nozzle body (150) into the respective well (300) of the carrier plate. (30), the sealing ring tightly surrounds the well (300) in the carrier plate (30), and the spraying device has a reservoir (156) for the substance to be applied to the test specimen or the substance mixture to be applied to the test specimen and a spray channel (153) which is provided with a compressed air connection at its end remote from the test specimen, the reservoir (156) and the spray channel (153) being connected to one another by a very narrow feed channel (157) which opens into the spray channel (153).
Special preference is given to a testing system wherein the spraying device comprises one or more micropipettes (158), each of which has a stock container (160) into which the substance or substance mixture is first introduced by suction, and then, using a piezoelectric droplet generator, one or more droplets of a well defined size are expelled through a nozzle (162) at a well defined rate and the test specimen is thus sprayed.
Special mention should also be made of an embodiment of the testing system wherein the nozzle body (150) has a plurality of linearly arranged nozzles and associated reservoirs and also spray and feed channels and sealing rings or a plurality of linearly arranged micropipettes (158), the distance (D) between the individual nozzles or micropipettes corresponding to the distance (E) between the wells (300) within a line of the carrier plate (30).
Especially preferred is a testing system wherein the nozzle body (150) comprises an air inlet channel (154) or channels and an air outlet channel (155) or channels, which are each so arranged that while the nozzle (151) is inserted in the respective well (300) of the carrier plate (30) the channels are in communication with the well (300).
The testing system according to the invention is especially suitable for testing insecticides, fungicides, herbicides, acaricides or nematicides, more especially insecticides, fungicides or herbicides.
The testing system according to the invention allows especially the testing of a very large number of substances and test specimens and reliable identification and categorisation of the test specimens and of the substances tested. Furthermore, contamination of neighbouring test specimens is reliably avoided and therefore the result of the test is not affected or falsified. Moreover, the testing system according to the invention enables operation to be, fully automatic to a greater or lesser extent, especially overnight and without supervision. The dependent patent claims relate to especially advantageous configurations of the testing system.